The Bacillus thuringiensis Cry1Aa toxin:: effects of trypsin and chymotrypsin site mutations on toxicity and stability

被引：24

作者：

Bah, A

van Frankenhuyzen, K

Brousseau, R

Masson, L

机构：

[1] Natl Res Council Canada, Biotechnol Res Inst, Montreal, PQ H4P 2R2, Canada

[2] Canadian Forest Serv, Great Lakes Forestry Ctr, Marie, ON P6A 2E5, Canada

来源：

JOURNAL OF INVERTEBRATE PATHOLOGY | 2004年 / 85卷 / 02期

关键词：

protease resistance; stability; toxicity; trypsin and chymotrypsin site mutation;

D O I：

10.1016/j.jip.2004.02.002

中图分类号：

Q95 [动物学];

学科分类号：

071002 ;

摘要：

The objective of the present work was to create an active Cry1Aa toxin showing enhanced resistance to degradation by spruce budworm (Choristoneura fumiferana) midgut proteases by mutating potential chymotrypsin and trypsin sites. Fourteen Cry1Aa mutants were created in an Escherichia coli-Bacillus shuttle vector and expressed in a crystal minus Bacillus thuringiensis host. Using spruce budworm gut juice, commercial bovine trypsin and chymotrypsin we performed protease resistance assays with Cry I Aa wild type and mutant toxins. Although many mutants showed little or no change, several mutants showed a >2-fold increase (R543S, R566G, and F570S) up to a >4-fold increase in toxicity (F576S), in bioassay studies against C fumiferana. The in vitro protease resistance assay results indicated a possible involvement of other gut juice components in toxin overdigestion. Published by Elsevier Inc.

引用

页码：120 / 127

页数：8

共 37 条

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